Self-priming centrifugal pump



May 15, 1951 J. SOUTHERN 2,553,056

SELF-PRIMING CENTRIFUGAL PUMP Filed May 5, 1945 h 2 Sheets-Sheet l @v eIUZTor May 15, 1951 J. SOUTHERN SELF-PRIMING CENTRIF'UGAL PUMP 2 Sheets-Sheet 2 Filed May 3, 1945 Patented May 15, 1 951 UNITED SELF-PRIMING CENTRIFUGAL PUMP John Southern, Newark, England Application May 3, 1945, Serial No. 591,643

In GreatBritain June 30', 1944 This invention relates to self-priming centrif' ugal pumpingv plant and has for its object the provision of a simple construction adapted to operate with efficiency. As compared with selfpriming pumps combining the usual eccentric water ring or hydroturbine type the improved pump possesses the advantage that instead of requiring unloading or disconnecting after the centrifugal pump has been primed, the priming element of the pump is adapted to assist the centrifugal pump by delivering in parallel therewith and without reduction of the maximum efficiency of the latter. The invention enables a priming pump to be employed which'is as small as consistent with the air handling capacity required', and as the liquid hand-led represents only a fractional portion of the total volume of liquid being pumped any loss in overall pumping efficiency of the combined unit is relatively small.

Further advantages achieved by the invention will hereinafter appear".

The invention consists in a self-priming centrifugal pumping unit having in combination a centrifugal pump and a vortex type priming pump as distinct from an eccentric water ring type with its suction connected to the suction of the centrifugal pump and its delivery connected to the discharge of the centrifugal pump so that the vortex pump operates as a vacuum pump during the priming of the centrifugal pump and as a liquid pump in parallel with the centrifugal pump after priming thereof.

The invention also comprises a self-priming centrifugal pump unit including a centrifugal pump and a vortex type priming pump having its suction connected to the centrifugal pump suction and, by a Joy-pass, to the discharge side of the centrifugal pump in rear of a non-return valve (preferably adapted to be shut off by the valve when the centrifugal pump is primed), and having its delivery connected with the centrifugal pump discharge in rear of said non-return valve.

According to one form the vortex pump is single-sided comprising a set of vanes co-operating with a single vortex or volute chamber in a plate or disc facing said vanes and enclosed in a shroud or annular sealing surface projecting from the vortex chamber plate or disc, the arrangement being such that the vortex impeller element is capable of lateral adjustment towards the plate or disc to compensate for Wear throughout.

The vortex impeller may be formed integral with the centrifugal impeller by the provision of vanes on the back of the centrifugal impeller 4 Claims. (01. 103- 113) element, or the vortex impeller maybe separate from the centrifugal impeller and may be in a compartment of the centrifugal pump chamber separated fromthe centrifugal impeller by par stop member in the path of the rotatin liquid causes a proportion thereof to be diverted to a lateral delivery, fresh liquid being drawn in through a lateral inlet. The pump may have a vortex chamber of decreasing cross-section in the: direction of whirl or the section may be constant or include a combination of parallel and tapered forms.

Further features of the invention will be hereinafter described.

In the accompanyin drawings.

Figure 1 is a cross section of a self-priming centrifugal pump unit according to one form of the invention in which the impeller vanes of the vortex pump are formed upon the back of the centrifugal impeller.

Figure 2 is an elevation looking from the fear at the back of the centrifugal impeller showing the vortex vanes.

Figure 3 is a front elevation of the vortex plate in which the vortex volute and inlet and delivery ports are formed, the delivery and suction connections being indicated diagrammatically.

Figure 4 is a fragmentary cross section of the j pump as seen in Figure l modified to. show an arrangement in which the vortex impeller and the centrifugal impeller are separate elements.

In carrying the invention into effect accordr' ing to one mode as applied to a single suction eye centrifugal pump and wherein the impellers of the centrifugal pump and vortex priming pump are embodied in a single unit, a centrifugal pump impeller has formed upon its back or rear face a series of radial vanes 2 extending from the hub toward a peripheral ring 2a and adapted to constitute a vortex pump impeller element." The combined impeller element is mounted upon a transverse haft 3 suitably mounted in bearings in a casing 4 which includesa centrifugal pump volute 4a of the usual form the discharge end of which is seen at 417'. The rear side of the chamber of the centrifugal pump is constituted by a plate 1 5 which also includes the vortex volu-te 5a of gradually decreasing cross sectional area with which the vanes '2 co-operate to-efiect the vortex pumping action. The inlet and deliveryportsof vided in the pump casing and is connected by a pipe 1 with the upper part of the suction chamber 4d of the centrifugal pump. The suction chamber 6 acts as a reservoir for flooding the inlet port 5b of the volute of the vortex disc. A delivery chamber 8 for the vortex pump separated from the chamber 6 by a wall 6a is provided in the casing, with which the delivery port. 50 of the vortex volute 5a communicates. The centrifugal pump discharge from the end 41) of the volute 4a has a non-return valve 9.

A by-pass 1a extends between the pipe 1 and a duct lb which may be conveniently formed in the spider of the non-return valve 9, the opening of the duct being towards the rear of the non-return valve, and the rear face of the valve 9 is preferably adapted to operate as a cut-off for the bypass duct 1b when the valve is fully open. Above the non-return valve a connection is established by the pipe Ill and the delivery chamber 8 of the vortex pump.

The vortex volute 511 has a gradually decreasing cross-sectional area in the direction of rotation of the vanes, i. e. clockwise as seen in Figure 3. The lateral inlet port 51) formed in the plate 5 connects the suction chamber 6 with the interior of the vortex pump, and the lateral outlet port 50 similarly connects thepump chamber with the delivery chamber 8. An annular projecting portion 511 on the plate 5 extends as a shroud over the ring or annular portion 2a of the vaned back of the centrifugal impeller and operatesas a sealing means.

A stop member 5e forming part of the vortex chamber is interposed between the two ends of the volute 5a, and acts to prevent complete rotation of the liquid in the volute. Rotation of the vortex vanes whirls the liquid which has entered through the port 51) and whirling liquid is forced into the adjacent decreasing volute 5a. Liquid travelling round the volute is obstructed by the stop member 5e and a condition of compression will be created at this point,'resulting in the discharge of liquid under pressure through the port 5c and into the delivery chamber 8. As the vanes pass the stop member 5e there will be a release of liquid from between the vanes into the beginning of the vortex volute thereby creating a suction condition which will cause more liquid to be drawn in through the port 5b. It will be seen that liquid is caused to move inwardly between the vanes adjacent the outlet port 50 and outwardly between the vanes adjacent the inlet port 5b, and that in this way the pumping action is maintained. The delivery chamber 8 lies on one side of the pump casing and has only one outlet, constituted by the pipe Ill. The suction chamber 6 of the vortex pump is located to the other side of the chamber 8 and receives liquid through pipes l and la as hereinafter described.

It will be appreciated that during the priming operation some loss of water 7 from the vortex pump will take place firstly through the delivery of the priming pump mixed with entrained air,

4 and secondly past the impeller sealing ring or shroud 5d, and that it is consequently necessary, particularly for long priming periods, to provide an adequate supply of sealing liquid for the vortex pump to make up for these losses. As indicated above the suction chamber 4d of the centrifugal pump, when the latter stops, retains sufficient water for supplying the sealing requirements of the vortex pump and similarly the suction chamber 6 of the vortex pump also acts as a reserve of sealing liquid.

On starting up, the residual liquid in the centrifugal pump is raised past and retained above the non-return valve 9 and is drawn off by the vortex pump through the by-pass passages 12, la into the chamberfi, where it is delivered by the vortex pump up the pipe ID to a position above the non-return valve 9 and is constantly recirculated during priming, this supply of liquid being capable of serving for sealing purposes over long priming periods. I

During priming the vortex pump operates as a vacuum pump, withdrawing air, via the pipe I, from the suction chamber 4d of the centrifugal pump. When the centrifugal pump is primed and is discharging, the non-return valve 9 seats itself against the orifice of the duct lb and so closes the by-pass to the pipe 1 and chamber-6.

When these conditions are established the vortex pump operates as a liquid pump discharging in parallel with the centrifugal pump through the pipe H1 in rear of the non-return valve 9.

According to a modification, instead of forming the vortex impeller vanes 2 on the back of the centrifugal impeller I, the vortex impeller may be a separate unit, as for example as seen in Figure 4. In this case the vortex impeller comprises. a disc 2b having a series of radial vanes 2 bounded by an annular ring or annulus 2a.

The vortex impeller may be conveniently located closely adjacent the centrifugal pump impeller but the vortex compartment may be separated from the centrifugal impeller chamber by a partition, I I, the vortex volute being formed in the plate or disc 5 similar to the plate 5 (Figure 1) and having a similar shroud portion 5d. In other respects the connection and arrangement of the combined unit may be substantially the same as that described with reference to Figure 1. l V V V In both forms it will be seen that the arrangement with the single-eye centrifugal impeller and the single set of vortex vanes co-operating with a single vortex volute, enable lateral adjustment of the vortex vanes element with respect to the volute chamber in the vortex disc or plate, to be readily effected to take up wear as such occurs between the vortex impeller element and the.

plate or disc. I

Thus for example in Figure 1 the required adjustment may be efiectedbyinserting washers of various thicknesses between the right-hand side of the boss of the impeller 2 and the adjacent shoulder on the shaft 3, and similar means may be employed in the form shown in Figure 4. Alternatively, the required adjustment can be made by endwise adjustment of the shaft 3 by the required amount, this being effected by the use of shims or other devices of known kind at the usual end thrust bearing (not shown) of th shaft 3.

I claim: a

1. A self-priming'centrifugal pump unit, comprising, in; combination, a centrifugal pump, a-

vortex type pump including a vaned impeller in a peripherally confined space, lateral inlet and discharge passages, and a stop member in the path of liquid rotated by the vanes to cause lateral delivery of said liquid, said vortex pump having an air extraction capacity sufficient for priming and a liquid capacity considerably less than that of the centrifugal pump, common drive means for the said pumps, a connection between the suction sides of the centrifugal and vortex pumps, and a connection between the delivery sides thereof whereby the vortex pump operates as a vacuum pump during priming of the centrifugal pump and as a liquid pump in parallel with the latter after priming thereof, a nonreturn valve in the discharge of the centrifugal pump arranged to afford a reservoir of sealing liquid for the vortex pump, and a by-pass from the rear of said non-return valve to the inlet of the vortex pump through which the latter receives sealing liquid from the residual liquid of the centrifugal pump,

2. A self-priming centrifugal pump unit according to claim 1, in which the said by-pass from the rear of the non-return valve is arranged to be shut off by said valve when the centrifugal pump is primed, and the connection between the vortex pump discharge and the centrifugal pump discharge is connected in rear of said non-return valve, whereby in priming the sealing liquid for the vortex pump is drawn by said pump from the residual liquid of the centrifugal pump delivered to the discharge side thereof for recirculation to the vortex pump while priming continues.

3. A self-priming centrifugal pump unit according to claim 1, in which said vortex pump includes an impeller having vanes on one side thereof, a plate facing the vanes and formed as a single vortex chamber co-operating with the vanes and having a stop member in the path of liquid rotated by the vanes to cause lateral delivery of said liquid, and an annular shroud extending from said plate for peripherally confining the impeller and vanes, said impeller being adjustable endwise towards the said plate to compensate for wear thereat.

4. A self-priming centrifugal pump unit according to claim 1 in which the vortex type priming pump includes vanes formed on the back of the centrifugal impeller and a vortex volute chamber formed in a plate, said chamber cooperating with the vortex vanes and including a stop member in the path of liquid rotated by the vanes to cause lateral delivery of said liquid, said disc or plate being formed to confine the impeller peripherally and also forming the rear wall of the centrifugal pump chamber, and in which the vortex pump vanes are peripherally confined by an annular shroud projecting from the plate which forms the vortex volute chamber, and the vortex pump impeller is adjustable axially towards the plate to compensate for wear.

JOHN SOUTHERN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,175,997 Saxe Oct. 10, 1939 2,278,595 Stelzer Apr. 7, 1942 2,321,810 Gurley June 15, 1943 2,368,528 Edwards Jan. 30, 1945 2,430,337 Heckert et al. Nov. 4, 1947 FOREIGN PATENTS Number Country Date 511,305 Great Britain Aug. 16, 1939 522,269 Great Britain June 13, 1940 

